A human cruciform binding protein (CBP) was previously shown to bind to cruciform DNA in a structure-specific manner and be a member of the 14-3-3 protein family. CBP had been found to contain the 14-3-3 isoforms beta, gamma, epsilon, and zeta. Here, we show by Western blot analysis that the CBP-cruciform DNA complex eluted from band-shift polyacrylamide gels also contains the 14-3-3sigma isoform, which is present in HeLa cell nuclear extracts. An antibody specific for the 14-3-3sigma isoform was able to interfere with the formation of the CBP-cruciform DNA complex. The effect of the same anti-14-3-3sigma antibody in the in vitro replication of p186, a plasmid containing the minimal replication origin of the monkey origin ors8, was also analyzed. Pre-incubation of total HeLa cell extracts with this antibody decreased p186 in vitro replication to approximately 30% of control levels, while non-specific antibodies had no effect. 14-3-3sigma was found to associate in vivo with the monkey origins of DNA replication ors8 and ors12 in a cell cycle-dependent manner, as assayed by a chromatin immunoprecipitation (ChIP) assay that involved formaldehyde cross-linking, followed by immunoprecipitation with anti-14-3-3sigma antibody and quantitative PCR. The association of 14-3-3sigma with the replication origins was maximal at the G(1)/S phase. The results indicate that 14-3-3sigma is an origin binding protein involved in the regulation of DNA replication via cruciform DNA binding.
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http://dx.doi.org/10.1002/jcb.10294 | DOI Listing |
iScience
December 2024
Guangzhou Municipal Key Laboratory of Metabolic Diseases and Reproductive Health, The Affiliated Guangdong Second Provincial General Hospital of Jinan University, Guangzhou, China.
AT-rich sequence can cause structure variants such as translocations and its instability can be accelerated by replication stresses. When human 16p11.2 or 22q11.
View Article and Find Full Text PDFNucleic Acids Res
December 2024
Department of Biology, Tufts University, Suite 4700, 200 Boston Ave, Medford, MA 02155, USA.
Long AT repeat tracts form non-B DNA structures that stall DNA replication and cause chromosomal breakage. AT repeats are abundant in human common fragile sites (CFSs), genomic regions that undergo breakage under replication stress. Using an in vivo yeast model system containing AT-rich repetitive elements from human CFS FRA16D, we find that DNA polymerase zeta (Pol ζ) is required to prevent breakage and subsequent deletions at hairpin and cruciform forming (AT/TA)n sequences, with little to no role at an (A/T)28 repeat or a control non-structure forming sequence.
View Article and Find Full Text PDFSoft Matter
December 2024
Department of Applied Chemistry, School of Chemistry and Chemical Engineering, Yantai University, Yantai 264006, China.
RSC Adv
November 2024
Institute of Physics, Faculty of Mathematics and Physics, Charles University Ke Karlovu 5, 121 16 Prague 2 Czech Republic +420 95155 1471.
Recently published observations have highlighted the presence of cruciform structures within the genome, suggesting their potential significance in the rapid recognition of the target sequence for transcription factor binding. In this study, we investigate the organization and stability of the (coding) strand within the Serum Response Element of the gene promoter ( SRE), specifically focusing on segments spanning 12 to 36 nucleotides, centered around the CArG-box. Through a thorough examination of UV absorption patterns with varying temperatures, we identified the emergence of a remarkably stable structure, which we conclusively characterized as a hairpin using complementary H NMR experiments.
View Article and Find Full Text PDFGenomics Inform
November 2024
Department of Biotechnology, Koneru Lakshmaiah Education Foundation, Vaddeswaram, Guntur, Andhra Pradesh, 522302, India.
The untranslated regions (UTRs) of genes significantly impact various biological processes, including transcription, posttranscriptional control, mRNA stability, localization, and translation efficiency. In functional areas of genomes, non-B DNA structures such as cruciform, curved, triplex, G-quadruplex, and Z-DNA structures are common and have an impact on cellular physiology. Although the role of these structures in cis-regulatory regions such as promoters is well established in eukaryotic genomes, their prevalence within UTRs across different eukaryotic classes has not been extensively documented.
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